*{
	margin: 0;
	padding 0;
	/*box-sizing: border-box;*/
}
body{
	background:aquamarine;
}
.containter{
	width: 1200px;
	margin:auto;
	overflow: hidden;
}
/*清除浮动*/
/*.container::after{
	content: "";
	display: table;
	clear: both;
}*/
.col{
	width: 33.333333%;
	height: 50px;
	background: aqua;
	float: left;
	/*border: 1px solid #f00;*/
}
@media (max-width:500px) {
	body{
		background:#f00;
	}
	.container{
		width: 100%;
	}
	.col{
		width: 100%;
		margin-top: 10px;
	}
}